As disclosed in Patent Document 1, a conventional chip resistor of the above-mentioned type includes a pair of terminal electrodes provided on both ends of an insulating substrate chip. The upper surface of the insulating substrate is formed with a resistor film electrically connected to the paired terminal electrodes. The chip resistor may be mounted on a printed circuit board by soldering.
Patent Document 1: JP-A-2000-133507
When the voltage of a power source is supplied to the printed circuit board carrying the chip resistor, the voltage is to be applied between the paired terminal electrodes. Since the single resistor film is provided between the paired terminal electrodes, all the power supplied between the electrodes concentrates on the resistor film. The concentration of the power on the resistor film increases the temperature of the resistor film. Accordingly, it is unpractical to use the chip resistor for a high-power circuit.
One way to address the above problem may be to arrange a plurality of resistor films in parallel on the upper surface of the insulating substrate between the paired terminal electrodes. With this arrangement, the power supplied between the paired terminal electrodes is divided into each resistor film. Hence, the temperature increase in the respective resistor films is suppressed, so that the chip resistor is applicable to a circuit to which high power is to be supplied.
The resistor film of a chip resistor is formed with a trimming groove. By forming a trimming groove, the resistance between the paired terminal electrodes is set to be within a predetermined allowable range.
In a chip resistor in which a plurality of resistor films are arranged in parallel between the paired terminal electrodes, each of the resistor films is electrically connected to the terminal electrodes. Thus, it is extremely difficult to make the dimensions of the trimming grooves of all the resistor films equal or substantially equal to each other. In other words, it is difficult to make the resistances of all the resistor films equal or substantially equal to each other. As a result, excessive temperature increase may occur at some of the resistor films which have a relatively high resistance.